Conventionally, a header tank of a heat exchanger such as a radiator is configured by integrally coupling a core plate that is made of metal and connects with each of tubes and a tank body that is made of resin and defines a space in the header tank. A gasket (i.e., a sealing member) that is made of an elastic material such as rubber is disposed between the core plate and the tank body. The gasket seals between the core plate and the tank body by being compressed by the core plate and the tank body.
Specifically, the core plate has a tube connection surface to which the tubes are connected and a groove that is formed in an outer periphery of the tube connection surface. A tip portion of the tank body on a side adjacent to the core plate is inserted to the groove of the core plate. The tank body is fixed to the core plate by crimping in a condition where the gasket is disposed between the groove of the core plate and the tip portion of the tank body.
According to such a heat exchanger, the groove is provided in the core plate. Accordingly, a length of the core plate in a flow direction of external fluid (i.e., air) becomes longer for the groove. Thus, a length of the heat exchanger as a whole in an airflow direction may become longer. Hereafter, the airflow direction will be referred to as a dimension in a width direction.
On the other hand, a heat exchanger in which the groove of the core plate is omitted to decrease the dimension in the width direction is disclosed (for example, refer Patent Literature 1). Specifically, according to a heat exchanger described in Patent Literature 1, a gasket is directly arranged on the tube connection surface of the core plate that is connected in a condition where the tubes are inserted to the tube connection surface. An end portion of the tank body is located on the gasket. The tank body is fixed to the core plate by crimping in a condition where the gasket is disposed between the tube connection surface of the core plate and the tip portion of the tank body.